Test new GIF mode for videos without sound

app/static/common.js

@@ -0,0 +1,32 @@
+function hasAudio (video) {
+    return video.mozHasAudio ||
+    Boolean(video.webkitAudioDecodedByteCount) ||
+    Boolean(video.audioTracks && video.audioTracks.length);
+}
+
+function setVideoInGIFMode(video) {
+    if (!hasAudio(video)) {
+        if (typeof video.loop == 'boolean' && video.duration < 3.0) {
+            video.classList.add("video-gif-mode");
+            video.loop = true;
+            video.controls = false;
+            video.addEventListener("mouseover", () => {
+                video.play();
+            })
+            video.addEventListener("mouseleave", () => {
+                video.pause();
+            })
+        }
+    };
+}
+
+var items = document.getElementsByTagName("video")
+for (var i = 0; i < items.length; i++) {
+    if (items[i].duration) {
+        setVideoInGIFMode(items[i]);
+    } else {
+        items[i].addEventListener("loadeddata", function() {
+            setVideoInGIFMode(this);
+        });
+    }
+}